Synthesis of Superhydrophobic Fluorescent Dyes Based on Coumarin-benzoxazole Derivatives and Their Dyeability Toward Unmodified Polypropylene Fibers

Three novel kinds of coumarin-benzoxazole-based superhydrophobic fluorescent dyes were synthesized. To induce the affinity to polypropylene, an extremely hydrophobic material, a dibutyl group was introduced into the coumarin moiety and one methyl, two methyl, and tertiary butyl groups were introduced into the benzoxazole moiety to obtain the three dyes, respectively. The optical properties of all three dyes were very similar because they were obtained via the introduction of different alkyl groups into the same fluorophore. Different alkyl substituents introduced into benzoxazole significantly affected its fluorescence properties, polypropylene affinity, and washability. In addition, the effects of dye concentration and dyeing temperature on the color strength and fluorescence emission intensity were investigated. Overall, the three developed fluorescent dyes applied well to the polypropylene fabric using the general dyeing method and showed excellent washability.